svn commit: r258328 - head/sys/net

[Alexander V. Chernikov]

On 19.11.2013 02:58, George V. Neville-Neil wrote:
> Author: gnn
> Date: Mon Nov 18 22:58:14 2013
> New Revision: 258328
> URL: http://svnweb.freebsd.org/changeset/base/258328
>
> Log:
>    Allow ethernet drivers to pass in packets connected via the nextpkt pointer.
>    Handling packets in this way allows drivers to amortize work during packet reception.
Great! First, but important step in kernel batching :)
>    
>    Submitted by:	Vijay Singh
>    Sponsored by:	NetApp
>
> Modified:
>    head/sys/net/if_ethersubr.c
>
> Modified: head/sys/net/if_ethersubr.c
> ==============================================================================
> --- head/sys/net/if_ethersubr.c	Mon Nov 18 22:55:50 2013	(r258327)
> +++ head/sys/net/if_ethersubr.c	Mon Nov 18 22:58:14 2013	(r258328)
> @@ -708,13 +708,25 @@ static void
>   ether_input(struct ifnet *ifp, struct mbuf *m)
>   {
>   
> +	struct mbuf *mn;
> +
>   	/*
> -	 * We will rely on rcvif being set properly in the deferred context,
> -	 * so assert it is correct here.
> +	 * The drivers are allowed to pass in a chain of packets linked with
> +	 * m_nextpkt. We split them up into separate packets here and pass
> +	 * them up. This allows the drivers to amortize the receive lock.
>   	 */
> -	KASSERT(m->m_pkthdr.rcvif == ifp, ("%s: ifnet mismatch", __func__));
> +	while (m) {
> +		mn = m->m_nextpkt;
> +		m->m_nextpkt = NULL;
>   
> -	netisr_dispatch(NETISR_ETHER, m);
> +		/*
> +		 * We will rely on rcvif being set properly in the deferred context,
> +		 * so assert it is correct here.
> +		 */
> +		KASSERT(m->m_pkthdr.rcvif == ifp, ("%s: ifnet mismatch", __func__));
> +		netisr_dispatch(NETISR_ETHER, m);
> +		m = mn;
> +	}
>   }
>   
>   /*
>